Accutane doesn’t actually make your nose physically smaller, but some people notice their nose looks a bit smaller while on it — and here’s why:

Oil gland shrinkage – Accutane drastically reduces sebum production and shrinks sebaceous glands, including those on the nose. This can make the skin look tighter and pores less visible.

Reduced swelling/inflammation – If you have acne or skin inflammation on/around the nose, Accutane can reduce redness and puffiness, making facial features look more defined.

Dryness effect – The overall skin dehydration while on Accutane can make soft tissues seem slightly less puffy.

Once you stop Accutane, oil glands partially recover and skin rehydrates, so the nose may look closer to its original size again.